1株野鸭源鸡贫血病病毒的分离鉴定及其编码区基因序列分析

利用MDCC细胞系从东北地区采集的死亡野生鸟类样品中分离获得1株禽类病毒,对该病毒进行特异性PCR、特异性间接免疫荧光法等系统鉴定后,证实该分离株为鸡贫血病病毒(CAV),命名为WDNE110501株.利用PCR方法克隆出其编码区基因片段,测序结果表明,WDNE110501株的编码区全长为1 823 bp,无碱基缺失或插入.并将该基因序列和推导的氨基酸序列与国内外已发表的34个CAV株编码区基因进行同源性和亲缘关系的比对分析,同源性为96.1％～99.8％;氨基酸的同源性为89.8％～99.7％,与国内毒株harbin的差异最小,与国外最近的是美国毒株98D02152.序列比较表明CAV的3个编码基因VP1、VP2和VP3均有一定程度变异,以VP1变异性最大,且在不同毒株间的这3个阅读框的氨基酸序列变异是互不相关的.这是首次在野生鸟类中分离出CAV病毒,提示了我们野生鸟类在鸡传染性贫血病病毒传播和分布中可能起到一定作用.     

Postulation of leaf-rust resistance genes in Czech and Slovak barley cultivars and breeding lines

Leaf‐rust resistance (Rph) genes in 61 Czech and Slovak barley cultivars and 32 breeding lines from registration trials of the Czech Republic were postulated based on their reaction to 12 isolates of Puccinia hordei with different combinations of virulence genes. Five known Rph genes (Rph2, Rph3, Rph4, Rph7, and Rph12) and one unknown Rph gene were postulated to be present in this germplasm. To corroborate this result, the pedigree of the barley accessions was analysed. Gene Rph2, as well as Rph4, originated from old European cultivars. The donor of Rph3, which has been mainly used by Czech and Slovak breeders, is ‘Ribari’ (‘Baladi 16’). Rph12 originates from barley cultivars developed in the former East Germany. Rph7 in the registered cultivar ‘Heris’ originates from ‘Forrajera’. A combination of two genes was found in 10 cultivars. Nine heterogeneous cultivars were identified; they were composed of one component with an identified Rph gene and a second component without any resistance gene. No gene for leaf rust resistance was found in 17 of the accessions tested. This study demonstrates the utility of using selected pathotypes of P. hordei for postulating Rph genes in barley.     

土壤—作物资源多目标优化配置分析

本文提出一种多目标土壤—作物资源优化配置的数量化分析方法,并对江苏省东海县土壤资源进行优化配置。结果表明：白浆土、岭砂土、包浆土、紫砂土等岗岭低产土应稳定小麦面积,压缩玉米面积,优先发展春花生、大豆、水稻;洼地砂姜黑土、水稻土应发展小麦—水稻和小麦—玉米两熟制,并适时换茬;介于上述两类土壤间的潮棕壤亚类和潮土类应大力发展小麦—花生两熟制。     

湟中马血清酯酶多态性的研究

采用聚丙烯酰胺凝胶电泳法对青海省湟中县９１匹马血清酯酶的多态性进行了研究。结果发现：①湟中马的血清酯酶受ＥＳ＾Ｆ，ＥＳ＾Ｉ，ＥＳ＾Ｓ和ＥＳ＾Ｏ４个等位基因的控制，其基因频率分别为０．４４５０，０．５３３０，０．０１１０和０．０１１０；②在被检湟中马的ＥＳ位点上共发现ＥＳ Ｆ，ＥＳ ＦＩ，ＥＳ Ｉ，ＥＳ ＩＳ和ＥＳ Ｏ五种表型，以ＥＳ ＦＩ为优势表型（４７．２５％）；③ＥＳ等位基因频率无性别差异；④     

LFA—3和IL—2对机体免疫增强作用

以绵羊红细胞膜提取的ＬＦＡ－３和猪外周血单个核细胞所产生的ＩＬ－２，同时或分别与新城疫Ⅳ系疫苗胸肌注射２２日龄雏鸡，测定鸡体ＨＩ抗体效阶及Ｅｔｇ花环形成率的变化，结果表明，ＬＦＡ－３组抗体效价与对照组差异极显著，ＩＬ－２也可显著提高ＩＶ系苗免疫后ＨＩ抗体效价，且两者的作用具有剂量依赖性。     

Multiple amino acid substitutions are involved in the adaptation of H9N2 avian influenza virus to mice

To explore adaptation of avian influenza virus to mice we previously performed serial lung-to-lung passages of the influenza A/Chicken/Jiangsu/7/2002 (H9N2) strain, resulting in the isolation of a variant influenza strain lethal for mice. We now report that virulence correlates with improved growth characteristics on mammalian cells and extended tissue tropism in vivo. Sequencing of the complete genomes of the wild-type and mouse-adapted viruses revealed 25 amino acid substitutions. Some were found to reiterate known substitutions in human and swine H9N2 influenza isolates. Functions affected include nuclear localization signals and sites of protein and RNA interaction, while others are known determinants of pathogenicity and host specificity such as the viral polymerase PB2 E627K substitution. These observations suggest that enhanced growth characteristics and modified cell tropism may contribute to increased virulence in mice. We conclude that multiple amino acid substitutions are likely to be involved in the adaptation of H9N2 avian influenza virus to mice.     

3个家蚕品种部分产茧量及体质量性状指标的协方差分析

养蚕生产中家蚕的桑叶食下量难以人为控制在同一水平,通常认为食下量会对蚕体生长发育及全茧量等产茧量指标产生显著甚至极显著影响。以山东省现行的3个春用蚕品种为材料,将食下量作为协变量进行协方差分析的结果表明,3个家蚕品种在3-5龄的蚕体质量增量、全茧量、茧层量性状指标上无统计学意义(P>0.125 2),仅个别指标均值间的最大差异在0.1水平下显著(P全茧量=0.066 9,P茧层量=0.056 1),因此该方法校正了用常规方差分析得出的上述性状指标在品种间存在极显著差异(P<0.000 1)的有偏结论,还明确了消化吸收量对上述性状指标影响不显著,可不作为协变量考虑。     

试论卡尔纳普的真理标准

卡尔纳普主张从哲学中清除形而上学。他拒斥行而上学．对综合命题提出了确证代替证实的标准,后来走向概率研究,为现代归纳逻辑发展开辟了新方向;对于分析命题则从句法分析到语义分析,为语言哲学和分析哲学作出了贡献。然而他主张的物理主义却并未成为现实。     

A meta-analysis comparing the effect of PCV2 vaccines on average daily weight gain and mortality rate in pigs from weaning to slaughter

The aim of this investigation was, through a meta-analysis, to review the published literature concerning the effect of PCV2 vaccination on the average daily weight gain (ADG) and on the mortality rate in pigs from weaning to slaughter. The review was restricted to studies investigating the effect of vaccines against PCV2 published from 2006 to 2008, identified using computerised literature databases. Only studies that met the following criteria were included: commercial vaccines were used, pigs or pens were assigned randomly to vaccination versus control groups in herds naturally infected with PCV2, and vaccinated and non-vaccinated pigs were housed together. Furthermore, it was a requirement that sample size, age at vaccination, and production period were stated. The levels of ADG and mortality rate had to be comparable to those seen in modern intensive swine production. In total, 107 studies were identified; 70 were excluded because they did not fulfil the inclusion criteria and 13 were identical to results published elsewhere. A significant effect of PCV2 vaccination on ADG was found for pigs in all production phases. The largest increase in ADG was found for finishing pigs (41.5g) and nursery-finishing pigs (33.6g) with only 10.6g increase in the nursery pigs. Mortality rate was significantly reduced for finishing pigs (4.4%) and nursery-finishing pigs (5.4%), but not for nursery pigs (0.25%). Herds negative for PRRS had a significantly larger increase in ADG compared to herds positive for PRRS. The PRRS status had no effect on mortality rate.